In the Garden:Mid-Atlantic
March, 2009
Regional Report

This sedum-covered greenroof bluebird house at the Morris Arboretum at the University of Pennsylvania has a customized opening to discourage predators.

Invite the Bluebirds

If you're fortunate enough to have bluebirds in your Mid-Atlantic meadow, they'll be in a courting mood about now, says Katharine Patterson, author and volunteer educator at the Irvine Nature Center, Owings Mills, Maryland. Watching beautiful, fluffy bluebirds is an endless pleasure; preserving them, a lifetime mission. If you need a practical reason to appreciate them, they devour insects as well as wild berries and fruits.

Bluebird expert Patterson recently spoke at the Mt. Cuba Center in Greenville, Delaware. She's been a "citizen scientist," caring for and studying bluebirds and their birdhouses, for 15 years. Patterson is strong in the "Bluebird Movement" begun in the 1920s to counter the influx of English sparrows invading the bluebird's habitat. Starlings followed, stripping berries and outcompeting bluebirds for food and habitat. In the 1970s, the bluebird population declined 90%, which movement members attribute to DDT's thinning effects on eggshells.

"So people started bluebird trails," Patterson explained. "We as human beings can help the species."

How can we bring bluebirds to our yards and meadows? Install properly built bluebird houses about 6 feet above ground, spaced about 100 yards per box, 50 feet from a tree, fence, or some place to perch. And treat them to a saucer full of mealworms.

Bluebird Season
From late February into mid-March, the male bluebird scouts out a home -- a safe nesting site in a tree cavity or a bluebird house. He perches himself nearby and sings in hopes of attracting a promising female who'll like him AND his chosen nesting spot.

If he's lucky, an interested female will check out his digs by hopping inside the cavity or nesting box. She's looking for a clean, dry nursery, so to speak. A pleased female will hang around. The two blues will cuddle, nestle, bill and coo, breed, and guard their new home.

Nest Building
The similarity to our human behavior is fascinating. We women tend to go shopping to outfit the nursery. The female bluebird goes looking for "pure dry grass" which she makes into a "sweet cup" shape for the nest. The male encourages her and protects their shelter (stays home from shopping).

Housecleaning
Those who have bluebird houses know they'll only be reoccupied if kept clean -- free of other bird's nests, sticks, old bluebird nests, debris. When building or buying a bluebird house, be sure one side is easy to open for cleaning.

From mid-February to mid-September, bluebird parents can have three broods -- five hatchlings in each brood from one bluebird box. With that in mind, it's best to remove the used nest each time the parents and fledglings have left. Patterson's Bluebird Nesting Timetable lists housecleanings for late May, mid-August, and mid-September.

Eggs to Nestlings to Fledglings
Parents who breed this March and April will have eggs in mid-April -- one egg daily, usually three to five eggs. Incubation lasts about 14 days through late April. Eggs start to hatch around May 6. Parents feed nestlings for about 17 days, till they're fully, feathered, fledglings ready to fend for themselves.

Later broods will hatch in late June and mid-August.

Our responsibility doesn't end with installing and cleaning the boxes. Add an anti-predator baffle, Patterson said. When nestlings appear, monitor the boxes so the peepers stay safe. Cats, rat snakes, crows, and flying squirrels can destroy the eggs. Starlings, English sparrows, and cowbirds often lay THEIR eggs in the nests.